It is known that cocoa butter-containing masses, particularly chocolate, which are processed in the molten condition, will develop, upon subsequent cooling and solidification, surfaces with desirable properties such as gloss, temperature resistivity, resistivity against fatblooming, etc., only if the molten mass has been subjected to a certain preparatory or pre-crystallization treatment which frequently is called "tempering". Those processes usually consist of successive heating and cooling steps which take place within a narrow temperature range of a few degrees Celcius only.
It is known that it is useful for those tempering processes to heat the mass initially to a relatively high first temperature at which all cocoa butter crystals are certainly molten regardless of their crystal modification. That first temperature is preferably selected to be about 45.degree. to about 50.degree. C. The melt which has been made crystal-free in that manner is then inoculated with crystal nuclei. In this connection, it has been found that the frequently used prior method to form locally solidified chocolate in the mass by cooling with relatively cold water and to stir the solidified chocolate as an inoculating material into the mass will lead to strongly fluctuating results, whereby that process is only little suited for a rational mass production wherein predictable and reproducible processes must take place. Therefore, processes have become known wherein the mass is cooled mildly, i.e. without the use of cold water, from the said first temperature to a second temperature which particularly is about 28.degree. to about 29.degree. C. At that temperature, the mass is stirred, and its viscosity increases up to a maximum. Then the mass is mildly heated, without overheating, to a third temperature at which the mass can be processed. That third temperature frequently is chosen to be in the range of about 31.degree. to about 32.degree. C.; that temperature, however, may particularly also lie in the range of about 33.degree. to about 34.degree. C., as it is stated in connection with a particularly advantageous method utilizing a two-stage cooling. During the cooling from the first to the second temperature, and during holding the mass (while stirring) at the second temperature, a process of pre-crystallization is initiated, and it has been found that an exact selection of the second temperature can be of importance for the processing and solidifying properties of the molten mass. In practice, the exact value of the second temperature has been determined experimentally for the particular composition of the mass under consideration, or it has been determined experimentally how long a given amount of a certain mass has to be cooled at a certain cooling intensity to arrive approximately at the desired second temperature--in that case, the cooling process was controlled simply by means of a switch clock which after lapse of a predetermined cooling time caused switching to the subsequent heating to the third temperature.
The last-described empirical methods are not always reliable. When the particular value of the second temperature which is in fact used for a certain mass is too high, i.e. if switching to the heating towards the third temperature is premature, the mass will have deteriorated crystallization properties. Similar disadvantages will result also if the cooling is extended for too long a time.